Inverse identification of material properties of rubber O-rings in hydrogen fuel cell electric vehicles

The demand for hydrogen storage and transport technologies as clean and sustainable alternatives to traditional fossil fuels is increasing. Rubber seals, such as O-rings, are key components of high-pressure gaseous hydrogen storage and dispensing systems, particularly in hydrogen fuel cell electric vehicles and hydrogen recharging stations. Owing to the large range of operating temperatures and constant exposure to high-purity, high-pressure hydrogen gas, these seals suffer from various types of damage that may result in premature failure. Difficulties arise when applying numerical techniques, such as finite element analyses, to predict such failures and assess lifetimes, as the material properties of the O-rings are unknown. Owing to the small sizes of the O-rings, standardized tests cannot be performed. In this study, the hyperelastic material properties of O-rings used in hydrogen fuel-cell electric vehicles are characterized using two newly developed component-wise testing methods. The contributions of various loading modes to the total reaction force were evaluated using finite element analysis-based digital twins and were used to decompose the test data into stress–strain responses. The stress–strain responses were used to identify the second-order polynomial strain energy density function. The evaluated material response resulted in an error of 3.55 % in validation by comparing the compression test results to the predictions from the finite element analysis predictions. The identified material properties were used in critical contact pressure analysis of the O-ring during high-pressure hydrogen refueling. A contact force loss of 8.99 % and 11.36 % was observed for contact pair between the inlet fitting and refueling tube, respectively. The analysis results show that the material properties identified through the proposed scheme can be used in numerical analysis to analyze the sealing performance.